Rock drill



Patented Feb. 21, I928.

UNITED STATES PATENT OFFICE.

ROYAL LEE, MILWAUKEE, WISCONSIN, ASSIGNOR TO LEE ENGINEERING RESEARCH CORPORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION WISCONSIN.

ROCK DRILL.

Application filed March 30, 1925. Serial No. 19,414.

The invention relates to rockdrills, more particularly of the hammer type.

The use of hammer drills has heretofore been limited to the drilling of holes ofonly a few feet in. depth, as the inertia of long and heavy drill bits materially decreased the speed of drilling, Furthermore, wear on the bits caused a reduction in diameter of the hole as the drilling progressed, which made it necessary when substituting a sharp bit to have it of smaller diameter than the preceding bit.

It is an object of the present invention to provide a hammer drill which can be used for drilling holes of great depth, this being effected by using comparatively short cutting members and closely associating the actuating mechanism therewith so that it may enter theihole being drilled.

Another object ofthe invention is to provide a hammer drill including radially expansible cutting means, whereby holes of substantially uniform diameter may be pro duced without danger of wedging.

The invention further consists in the seva eral featureshereinafter set forth and more particularly defined by the annexed claims.

In the accompanying drawings, Fig. 1 is'a longitudinal sectional view of a rock drill embodying the inventionin operative position' 2 is a bottom end View thereof;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1; v

Fig. 1 is a sectional view taken on the line 1-4 of Fig. 1

- Fig. 5 isv a sectional view taken on the line 55 of Fig. 1;

Fig; 6' is a detail perspective view of one of the cutting members; and v Fig. 7 is a fragmentary longitudinal sectional view of a modified form of drill embodying the invention. V

In the. drawings, 10 designates a cylinder which closed at its upper end by a nipple 11 threaded therein and receiving the threaded end of a. coaxially-disposed air supply pipe 12 The pipe 12 is adapted to support the cylinder and may be formed of sections joinedtogether by couplings, (not shown) as in the case of rotary deep well drills.

The actuating mechanism illustrated. in the drawings is of the well-known hammer type preferably having valveless operation in order to. obtain compactness. Compressed air is conducted from the nipple 11 through aport 13, communicating with an annular recess14. A hollow hammer or piston 15 is slidably mounted in the cylinder and is pro vided with a shoulder 16 against which the pressure of the air is constantly exerted for effecting retraction of the hammer. On beginning the forward stroke of the hammer, ports 17 in the head of the hammer are in communication with the annular recess 1% and serve to admit live air into and behind the hollow hammer. Since the. area thus presented to air pressure is much greater than the area of theishoulder 16, the hammer is driven forward to a point where the ports 17 communicate with an annular chamber 18 into which the air is exhausted, whereupon the air pressure on the Shoulder 16 then retracts the hammer.

At the end opposite the nipple 11, the cylinder 10 is provided with a threaded projection 19 onto which a sleeve member 20 is removably secured, the sleeve member being preferably of the same outer diameter as the cylinder. An anvil pin 21 is provided with a polygonal upper end 22 .slidably fitting withina corresponding axial opening 23 in the cylinder and projecting into the annular chamber 18 in position to be struck by the hammer 15 on its power strokes. A flange 24: on the anvil pin 21 is adapted to engage a boss 25. within a bore 26 in the end of the cylinder for limiting the inward movement of the anvil pin. A cylindrical cup 27 formed of complementary halves 28 is adapted to fit in the bore 26 wherein it is yieldingly held by a spring 29 engaged by an inwardly extending flange 30 in the sleeve 20. The flange 24 on the anvil pin is adapted to engage the spring pressed cupfor yieldingly limiting the outward movement of the pin. The pin, however, may be readily removed by unscrewing the sleeve. 20 from the cylinder 10.

The outer end of the anvil pin 21 is provided with radially-extending tapered wings or projections 31 which are adapted to enter. correspondingrecesses 32 near the outer ends of drill bit members 33. In the present in stance, three complementary bit members are shown and together form an expansible bit surrounding the anvil pin 21. The inner'or upper ends of the. bit members fit, closely together about the anvil pin and areeach provided with a bead 3t adapted to bear .pin 21.

against the inner wall of the sleeve 20 and fulcrum thereon, the sleeve forming a housing for the bit members. The outer end of each bit member projects beyond the end of the sleeve 20 to form a cutting portion and is preferably provided with a plurality of hardened radially-disposed cutting ridges 35 which together form the rosette shown in Fig. 2 of the drawings. The cutting ends of the bit members are flared so that they may swing radially outwardly to a cutting diameter larger than the sleeve 20 and the cylinder 10, and the bit members are limited in such movement by the engagement of a lower cylinder portion 36 on the bit members with the lower inner walls of the sleeve member 20; The radially extending wings or projections 81 on the anvil pin 21 are provided with inclined end surfaces 37 engageable with inclined surfaces 38 in the recesses 32, so that the reaction of the bit members wnen resting on the bottom of a hole serves to cause their radial expanding movement. The anvil pin 21 is preferably provided with a longitudinal bore 39 to conduct exhaust air from the chamber 18 to the end portions of the bit members. In addition to this air passage, other air passages 10 may be provided connecting the chamber 18with the bore 26, and the cup sections 28 may be provided with air passages 41. Also,

the upper beaded ends of the bit members may be provided with air passages 42 and the lower ends of said members may be 131'0. vided with air passages 43, which latter passages may be dispensed with, if dcsircd, as the interstices between the bit members may afford sufficient passage for exhaust 'air.

In the modified form of the invention shown in Fig. 7, the cutting surface of the bit members-33 is concave so that the engagement of the cutting surface 35 with the conical rock face 44 produced by it will serve to effect the outward radial movement of the bit members when the device is in operation. Also, in this construction the radially-eatending projections 31' of the anvil pin 21 need not be provided with the taper present on the projections of the anvil In operation, the device held against a rock face'and compressed air is admitted through the pipe 12 for effecting reciprocation of the hammer 15. The anvil pin 21 receives the hammer blows and through the projections 31 transmits them to the drill bit members Under the impact of the hammer blows, the cutting edges of the bit members'ehip the rock with which they engage and produce an opening which is larger than thecylinder by reason of'the radial eXpa-n-' .sien of the drill bit. This leaves an annular space about the cylinder, 10 and sleeve 20 hrough which the chipsancl dust may be discharged by theexhaustair issuing from the open end of the sleeve, and the presence of the exhaust air within the sleeve serves to prevent the accumulation of chips therein.

It will be seen that in swinging outwardly the bit members pivot about the .beads 3 f at their inner or upper ends which rest against the inner walls of the sleeve 20.

As wear tends to cause a reduction in the diameter of the drill bit, the diameter of the hole being drilled is not materially affected because of the outward radial movement permitted of the bit members. This freedom of v movement also prevents the sticking or fitchering of the bit in the hole. While the drill is operating the bit may be rotated by means of the pipe 12, as the anvil pin is non-rotat'ably mounted in the cylinder. After the bit has been in operation sufficiently long to require sharpening, the bit members may be readily replaced with sharp ones by unscrewing the sleeve 20, and the fresh bit members may be identical withthose being replaced, which permits them to be sharpened on the same dies. The with drawal of the drill from the hole may be easily effected as the contraction of the bit at such time will prevent its wedging in the opening.

At times when there is no solid material under the bit members and blows aregbeing struck by the hammer, the spring '29 serves to absorb the energy. of the blows, which might otherwise rack the device.

If desired, water may he introduced down it is necessary to furnish compressed air at sufficient pressures to permit the removal of such water together with the sludge which forms. 1 1

The invention provides a simple and effecti ve means for drilling holes of greatv depth and substantially uniform diameter, and as the cutting members are comparatively short,

. the effectiveness of the blows remains substantially constant at all depths.

lVhat I claim as new and desire to secure by Letters Patent is: I i

1. In a rock drill, the combination of an air cylinder having a recrprocable piston therein forming a hammer, and a plurality of hammer-blow-operated cutting members actuated by said piston and movable apart while drilling, said cuttingmembers each receiving actuating blows at an intermediate portion- '2 In a rock drill; the combination of acaslng having an air cylinder disposed coaxially therein, a sleeve carried at the lower end of said casing, and a plurality of piston actuated cutting members mounted Within said sleeve and movable apart at their outer projecting ends for drilling an opening capable of admitting said casing and sleeve.

3. In a rock drill, the combination of airoperated percussion means including an anvil member, a plurality of cutting members co-operating therewith to receive blows therefrom and movable apart at their outer ends while drilling, and means for limiting 116 outward movement of said cutting memers.

4. In a. rock drill, the combination of airoperated percussion means including an anvil member, a plurality of cutting members surrounding said anvil member and having an operative connection therewith for receiving blows therefrom, said cutting members being radially movable with respect thereto at their outer cutting ends for permitting an outward disposition of said members while drilling.

5. In a rock drill, the combination of airoperated percussion means including a cylinder and an anvil pin having a limited axial movement therein, and a plurality of complementary cutting members surrounding said pin and having an operative connection therewith, the outer ends of said cutting members having a limited radial expanding movement. I

6. In a rock drill, the combination of a cylinder, an anvil pin axially movable therein, air-operatedmeans for striking said anvil pin, a plurality of complemetary cutting members surrounding said pin and having an operative connection therewith, and a sleeve member carried by the cylinder and surrounding said cutting members, said cut ting members having cutting portions pro- 1ect1ng able while drilling to a cutting diameter greater than said sleeve and cylinder.

7. In a rock drill, the combination of a cylinder, an anvil pin slidably mounted therein, air-operated means forstriking said anvil pin, a plurality of complementary cutting members surrounding said anvil pin and having radially-extending openings therein, there being radially extending projections on said anvil pin adapted to enter said openings for transmitting blows to said cutting members but permitting 'a radial outward movement of said cutting members while drilling.

from said sleeve and radially mov- 8. In a rock drill, the combination of cylinder, an anvil pin axially movable therein and provided with an intermediatelydisposed flange limiting its inward movement into said cylinder, air-operated means for striking said anvil pin, a spring-pressed member surrounding said anvil pin for limiting the outward movement of said anvil pin, and a plurality of complementary cutting members'operatively connected to said anvil pin and having their outer ends radially movable to permit an increased separation of said members while drilling 9. In a rock drill, the combination of a cylinder, a sleeve member carried thereby, an anvil member axially movable in said cylinder, airoperated means for striking said anvil. member, cutting members disposed within said sleeve member and having an operative connection with said anvil member, said cutting members having their innerends pivotally engaging the inner wall of said sleeve and having their outer cutting ends projecting from said sleeve and radially movable to obtain a cutting diameter larger than said sleeve while drilling.

10. In a rock drill, the combination of a cylinder, an anvil pin axially movable therein and having an intermediately disposed flange adapted to engage the cylinder for limiting its inward movement therein, a cup member surrounding said anvll pin, a spring bearing on said cup member, asleeve mounted on the end of said cylinder and having an inwardly projecting flange on which said spring is seated, radially expansible complementary cutting members disposed .within said sleeve and having an operative connection with said anvil pin for receiving blows therefrom, the cutting ends of said cutting members projecting from said sleeve and movable while drilling to a cutting diameter larger than said sleeve.

11. In a rock drill, the combination of airoperated percussion means including a reciprocable blow-transmitting member, and a plurality of cutting members each having an operative engagement at an intermediate portion with said blow-transmitting member and movable apart at their outer ends while drillin t In testimony whereof, I afiix my signaure.

ROYAL LEE. 

